Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

Forum Discussion

smalex_355988's avatar
smalex_355988
Icon for Nimbostratus rankNimbostratus
Apr 23, 2018

DNS Failover Mechanism

Apologize for a very basic question. We have one F5 DNS in DC and one in DR. For our domain abc.com, in the service provider, Authoritative DNS is DC DNS & DR DNS. As per my understanding, ISP would...
application delivery
BIG-IP DNS
Faruk_AYDIN's avatar
Faruk_AYDIN
Icon for Altostratus rankAltostratus
Apr 23, 2018

Round robin is the default behavior of DNS servers. You must have two records for name server of your domain. One is DC DNS, the other is DR DNS. All requester receive these two records but the order changes every request. For example, in the first response, let DC DNS be the first record, and DR DNS be the second record, as for the second request DC DNS will be the first record, and DR DNS will be the second record.

 

If DR DNS is down, this means no response, then client tries the other record(DNS), in our example: DR DNS.

 

That is it.